Nectarine tree named ‘Sunbest’

ABSTRACT

A new and distinct variety of nectarine tree, denominated ‘Sunbest’, has a low winter chilling requirement estimated at 225 chill units (cu). The tree is of medium size, has a moderate vigorous and upright growth habit. It has non-showy, pink flowers and leaf glands are small, with reniform shape. Trees of ‘Sunbest’ are self-fertile and regularly bear heavy annual crops of early season fruit that are large for its ripening season. Fruit are uniformly firm and yellow with melting flesh which are semi-freestone. Fruit are oval, and uniform with substantially symmetrical shape, and have an attractive 90 to 100% bright red skin. The fruit of ‘Sunbest’ ripens about 3 to 5 days before ‘Sunraycer’ nectarine in early May at Gainesville, Fla.

Botanical classification: Prunus persica.

BACKGROUND OF THE NEW VARIETY

The present invention relates to a new and distinct variety of nectarine[Prunus persica (L.) Batsch] tree adapted to a subtropical (low chill)winter climate. This new tree, named ‘Sunbest’, produces highly colored,good eating quality, semi-freestone, melting flesh fruit for freshmarket in early May at Gainesville, Fla. Contrast is made to ‘Sunraycer’(unpatented) nectarine, a standard variety, for reliable description.‘Sunbest’ is a promising candidate for commercial success in that it haslarge, attractive red skin, sweet fruit that ripen evenly.

ORIGIN OF THE VARIETY

‘Sunbest’ nectarine tree (genotype) originated in a cultivated area ofthe fruit breeding program at the University of Florida, located atGainesville, Fla. where it was tested. The seed parent was ‘Sunraycer’nectarine and the pollen parent was ‘Suncoast’ (unpatented) nectarine.‘Sunbest’ nectarine was selected in 1994 because it exhibited yellow,melting flesh, in a large fruit with a bright red skin. It wasdesignated and tested as Fla. 94-15n. It was asexually propagated bybudding onto ‘Flordaguard’ (unpatented) seedling rootstock (forroot-knot nematode control) and determined to have unique tree and fruitcharacteristics making it worthy for commercial fresh fruit production.There are no known effects of this standard rootstock on this scioncultivar. Asexually propagated plants remained true to the original treeand all characteristics of the tree and the fruit were transmitted.

SUMMARY OF THE VARIETY

The new and distinct variety of nectarine tree bears moderately earlyripening fruit, and has a low chilling dormancy requirement. ‘Sunbest’blooms (non showy flowers) with ‘Sunraycer’ nectarine in early Februaryat Gainesville. The estimated chilling requirement is 225 chill units,based on bloom 1 to 2 days before ‘Sunraycer’. ‘Sunbest’ nectarine treeis characterized by bright red skin fruit having firm, melting andyellow flesh. Fruit are semi-freestone and of good flavor and eatingquality. The trees are vigorous, productive and regular bearing. Treesattain in two years, a height of two meters and a spread of one and ahalf meters at Gainesville. Terminal growth of up to a half meterannually is common on mature five-year-old trees with normal pruning toa vase shape.

The first fruit ripen in early May at Gainesville or in about 80 to 85days from full bloom, which is about 3 to 5 days before ‘Sunraycer’. Thefruit are uniformly large (about 20% larger by weight than ‘Sunraycer’)for an early-mid season nectarine. Ripe fruit have 90 to 100% solid (nostripes) red skin with a small amount of red pigment in the flesh at thetip end of the fruit, especially on trees stressed during hot, dryweather. There is no red pigment in the flesh at the pit. The floweranthers are light red to yellow, and leaf glands are reniform, commoncharacteristics of many standard nectarine varieties.

DESCRIPTION OF THE DRAWINGS

The accompanying drawing is a color photograph which shows a typicalspecimen of the fruit, leaf, and stem of the new variety as nearly trueas it is reasonably possible to make in a color illustration of thistype.

The photograph shows an attractive shape and exterior coloration of fourspecimens of fruit above a ruler in side view, stem end view, a blossomend view, a side view showing the suture and a fruit cut longitudinallyto show the pit.

DETAILED BOTANICAL DESCRIPTION

The tree, flowers, and fruit may vary in slight detail due to variationsin soil type, cultural practices, and climatic condition. The potentialfor commercial production of fresh fruit by ‘Sunbest’ is high, due toits attractive red skin over a bright yellow ground color, large fruitof good flavor, and good firmness with even ripening throughout thefruit. The present botanical description is that of the variety grown on5-year-old trees on ‘Flordaguard’ rootstock under the ecologicalconditions prevailing at Gainesville, Fla. Colors (except those incommon terms) are described from “The Pantone Book of Color”, publishedby H. N. Abrams, Inc., N.Y. 1990.

Tree:

Ploidy.—Diploid

Size.—Trees are medium stature when trained to an open vase form.

Vigor.—Moderately vigorous, and must be summer and winter pruned whengrown to a vase shape to keep the tree open to get strong fruiting woodin the lower center. Trees respond typically to irrigation andfertilization. Tree growth of 4 to 6 feet in height and 3 to 5 feet inwidth occurs the first growing season in the field.

Density.—Light to medium in branching habit. Foliage density is high dueto short internodes (8 to 11 nodes/10 cm shoot length). Internode lengthis shorter than in most standard varieties. Pruning is required to openthe tree center to promote sunlight entrance for enhancing fruit colorand sugar.

Form.—Semi-upright, but easily spread when pruned to vase shape.

Hardiness.—Hardy with respect to typical north central Florida winters.

Bearer.—Very productive annually without alternate bearing observed.Trees are self fertile and must be fruit thinned to avoid limb breakageand obtain large fruit size. Yields equivalent of 200 bushels (50 lbs.each) per acre have been obtained on 5-year-old hand thinned trees undera commercial simulated orchard culture at Gainesville. Trees annuallyset several times the number of fruit for a desired crop load.

Chilling requirement.—Estimated endodormancy chilling requirement is 225chill units based on time of bloom and leafing.

Trunk:

Size.—Medium trunk diameter attaining 8 cm diameter at a height of 30 cmat the end of 3 years growth at Gainesville.

Texture.—Medium smooth, but changes to medium shaggy as tree ages.

Bark color.—Older bark gray, Chinchilla (Pantone 17-1109).

Lenticels.—Numerous (23 per 4 square inches of surface area of trunk)and small (2-5 mm length perpendicular to the trunk) with the centerbeing yellowish brown, Medal Bronze (Pantone 17-0942).

Branches:

Size.—Strong growth of scaffold branches. Fruiting branches mostly largediameter (4 to 6 mm) and not overly numerous, resulting in strongfruiting wood. Thus, the tree growth and structure permits easier andfaster winter pruning.

Texture.—Relatively smooth, numerous lenticels attaining size found ontrunk and old scaffolds. Roughness increases with age.

Color.—New wood is light green, Pale Star (Pantone 12-0626); Old wood ismore brown, Ash (Pantone 16-3802).

Crotch angles.—Angles are selected at 45 to near 90 degrees in firstyear of tree training. Natural angles are within the normal range ofstandard varieties for a semi-upright tree.

Leaves:

Size.—Medium; 13 to 17 cm length, including the petiole; 3 to 4 cmwidth. Measurements were made on vigorous upright shoots of summergrowth.

Thickness.—Regular and average for commercial nectarine varieties.

Form.—Lanceolate.

Apex.—Acute.

Margin.—Serrulate, slightly undulate.

Base.—Cuneate.

Surface.—Upper, glabrous; Lower, medium large veins that are pinnatelynetted.

Color.—Lower surface is green, Avocado(Pantone 18-0430); Upper surfaceis slightly darker green, Mosstone (Pantone 17-0525). Petiole andmid-vein show red anthocyanin in autumn, characteristic in peach andnectarine for 85 to 90 days or less in fruit development period (bloomto ripe).

Glands.—Two to 4, small, reniform glands mostly on lower leaf blade, butoccasionally on petiole. Leaf glands are moderately smaller than thoseon most commercial varieties. Leaf glands on young leaves are lightgreen, Leek Green (Pantone 15-0628), darkening to Green Moss (Pantone17-0636) on older leaves in mid-summer.

Petiole.—About 1 cm (0.8 to 1.1 cm) length; 1.3 mm diameter. Lightgreen, Poison Green (Pantone 16-6444) darkening to Plantation (Pantone18-0832) on older leaves of summer. Grooved longitudinally.

Stipules.—Medium (equal to most commercial peach varieties), usually 2per bud, and abscising just before leaf becomes full size in summergrowth.

Arrangement.—Alternate.

Flower buds:

Hardiness.—Hardy with respect to north central Florida winters (16Fminimum observed).

Abundance.—Very high due to shorter than average internode length. Mostbuds set fruit in absence of spring frosts and show little evidence ofbud drop.

Size.—Medium, average 3.5 mm length in mid winter.

Form.—Plump, conic and free.

Surface.—Pubescent scales.

Color.—Brown, Stucco (Pantone 16-1412) in late summer.

Flowers:

Blossom period.—One to 2 days before ‘Sunraycer’ nectarine — average 50%bloom February 5 to 10 most years at Gainesville, but occurring over a7-10 day period. Time and length of bloom are dependant on ambienttemperature.

Aroma.—Slight and pleasant.

Flower density.—Abundant, varying 1 to 4 per node, but usually 2.Density very high due to reduced inter-node length (see tree density).

Type.—Non-showy, location and seasonally variable within the range ofcommercial non-showy varieties. Average flower diameter — 22 mm. Averagepetal length, 10 mm; width, 5 mm. Texture smooth.

Color.—Orchid Pink (Pantone 13-2010) at flower opening, and within thepink range of standard varieties.

Flower parts.—Stamens and pistil size, shape and color are within therange of standard commercial varieties. There are 5 sepals and petals.Sepals average 4 mm length and 3 mm wide at attachment to calyx cup andtriangular shape with a dull point at the distal end. Sepals are green,Amber Green (Pantone 17-0840) on the exterior with a smooth pubescentmargin. Sepals are pubescent and petals are glabrous. Pistils areusually 1 per flower. Pistil length (from tip of stigma to base ofovary) averages 11 mm. Pistils are light green, Pale Star (Pantone12-0626). Flower pedicel is 1 to 2 mm length.

Calyx cup.—Medium small in the size range of commercial varieties. Cupdiameter is 5 mm at the time of flower opening and internal color isorange, Tangerine (Pantone 15-1247).

Stamen.—Anthers are light red to yellow, Orange (Pantone 16-1253), atflower opening, fading to yellow, Banana (Pantone 13-0947), beforepollen sheds, common to many nectarine varieties, regular size. Numberof anthers varies from 25 to 36, length is 7-9 mm. Filaments are lightgreen, Pale Star (Pantone 12-0626).

Pollen.—Abundant and bright yellow, Snapdragon (Pantone 13-0840), commonto many nectarine varieties.

Fertility.—Fully self fertile, and no cross pollination is required.Fruit set is abundant.

Fruit:

Maturity when described.—Tree ripe, May 3, 2001 at Gainesville.

Date of picking.—First, May 1, 2001; Last, — May 8, 2001 at Gainesville.

Size.—Uniform, medium large (large size for early mid-season maturity at120 to 140 g). Varies with fruit number per tree, soil type, climaticconditions and cultural practices. Average equatorial diameter — 2⅜inches (59 mm). Average polar length (stem to distal end) — 2⅝ inches(65 mm).

Pedicel size.—Length is approximately 7 mm; Width is approximately 3 mm.

Longitudinal section form.—Strongly oval.

Transverse section through diameter.—Round.

Suture.—Shallow and inconspicuous.

Ventral surface.—Usually rounded.

Base.—Slightly cordate.

Apex.—Usually rounded to slightly obtuse.

Crater at stem attachment.—Flaring circular with fruiting branchdepressing on base of fruit. Depth is 6 to 9 mm; breadth is 18 mm at topand 4 mm at pedicel attachment.

Skin.—Thickness — Medium in comparison to commercial nectarinevarieties. Texture — Medium in comparison to commercial nectarinevarieties. Tenacity — Tenacious to flesh. Color — Bright red, FlameScarlet(Pantone 18-1662), over 90 to 100% of skin. Ground color isbright yellow, Sunset Gold (Pantone 13-0940). Fruit exposed to sunlighthave a higher degree of enhanced red skin. Tendency to crack — Noneobserved. Taste — No astringency observed. Epidermis — Glabrous, waxyand smooth.

Flesh.—Ripens — Evenly within each fruit. Texture — Firm, juicy, meltingwhen fully ripe. Fibers — Very fine, small, tender, and abundant. Aroma— Moderate and in the middle range of commercial nectarine varieties.Eating quality — Good, moderately sweet, slightly acid. Soluble solidswere about 11 brix and titratable acid was 0.86 at 0.9 Kg penetrometerfirmness. Juice — Abundant. Color — Yellow, Amber Yellow (Pantone13-0942), with slight speckled red in the flesh near the fruit tip,especially on stressed trees under dry, hot conditions. There is no redat the pit. Browning by oxidation — Very slight on tree ripe fruitbeginning to soften. Amygdalin — Undetected.

Stone.—Type — Semi-freestone. Size — Medium small: average length is 30mm; average width is 23 mm; average thickness is 18 mm; average wallthickness is 5-6 mm. Color — Grey Sand (Pantone 13-1010) when freshlyexposed.

Form.—Oblong. Base — Straight. Apex — Acute. Sides — Near equal. Surface— Irregularly furrowed toward the ventral edge, pitted from base toapex. Ridges — Jagged toward the base. Tendency to split — Noneobserved.

Seed.—Bitter (amygdalin is abundant) kernel. Viable if stratified uponremoval from fruit at harvest, and without drying. Kernel is brown,Sunflower (Pantone 16-1054) when first removed from ripe fruit. Side is14 mm length, 9 mm wide and 3.5 mm thick. Shape is acute tip with obtusebase and overall ovate shape.

Use—Fresh; dessert.

Resistance to disease—High resistance to bacterial spot incited byXanthomonas campestris pv. pruni (Pers.) Diet. Resistance to other fruitand tree diseases are within the range for commercial nectarinecultivars in Florida. No unusual resistance or susceptibility to insectsand diseases noted.

Keeping quality—Excellent after 10 days at 2C. and with minimal bruisesor scarring appear on skin.

Shipping quality—Degree of firmness at harvest and firmness retained inrefrigeration for 10 days at 2C, with no internal breakdown of flesh orappreciable loss of eating quality, indicates fruit should be highlyacceptable for shipping.

I claim:
 1. A new and distinct nectarine tree variety as illustrated anddescribed, characterized by a low chilling requirement, and bearingfruit having firm, yellow and melting, semi-freestone flesh of higheating quality and an attractive, high percentage red skin with fruitripening in early May or about 3 to 5 days before ‘Sunraycer’ atGainesville, Fla.